The discussion below is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.
Force measuring transducers require periodic calibration via comparison of the transducer under test to a reference standard transducer. Calibration must be performed at a range of incremental forces, per international standards. In many cases, the testing machine for performing the test can be used as the force applicator for calibration purposes; however, in some situations this is not possible or the resulting fixturing needed to perform the calibration introduces an unacceptable error.
In one such case, an electrodynamic driven material testing system has the unique characteristic that its short term dynamic force capability exceeds its static force. Its dynamic rated force can be maintained for a duration shorter than required for calibration. Therefore, an alternate means of force application is required to achieve the full range.
In other systems, the controller or control system is not capable of performing the test needed for calibration. Likewise, the structure of some systems do not allow for in-situ calibration. For those machines that allow in-situ calibration, the coupling and fixturing technologies currently used are not accurate enough for the latest high accuracy standards that must be met. Although methods and apparatuses have been used to apply external loads, these have proven incapable of producing repeatable results with high accuracy.